Hello.

Would like to hear a comment about this from DJI staff.

I set my altitude to 80m. I lost connection because i went out of line of sight(yes, my choice, my risk, not topic here). RTH is initiated as intended but when it ascend it only go to 50m and it almost hit some trees, on the way back to me, that would have been avoided if it acceded to 80m as i set it to.

Lucky OA was available but light was not very good and an hour later, OA would not be available because of lack of light.

I wonder if the drone does this because OA IS available and if it weren't, it would go to 80m. But even if this is the case, i don't like that. It is a risk. Could hit small branches etc.

So! Have anyone else had this and can DJI comment if this is working as you want or is it maybe a bug?

In the last part of this video you can see it happen:

I am not staff so I hope you don't mind if I comment.

It would be nice if you over-layed your altitude reading so we could see the measured height as it happens.

How cold was it?  I had my P2V+ RTH in -4C, 25F a few weeks ago (pre-warmed battery and AC) and it only rose to 200 ft rather than the 250 it was supposed to rise.  I don't have an explanation other than the air temp was very cold - outside of the air temp parameters I'm supposed to fly.  

Mark The Droner Posted at 2017-3-6 03:09
I am not staff so I hope you don't mind if I comment.

It would be nice if you over-layed your altitude reading so we could see the measured height as it happens.

Hi. Of course you can comment.

I will try to share my log of the flight here once i figure out how.

It was not very cold. I don't remember exact but i'm sure it was over 0c.. maybe 5 or even more. Didn't use gloves and my hands wasn't cold.

If you upload your log to http://www.phantomhelp.com/LogViewer/upload/ and post a link then we might be able to see the explanation, it should show us what RTH height it was set to and what it did on RTH...

Could have done with Active Track to track the bikes, would have been smoother, preferably with reverse flight enabled...

Was that a bonfire on the ice at the end?

Nigel_ Posted at 2017-3-6 03:26
If you upload your log to http://www.phantomhelp.com/LogViewer/upload/ and post a link then we might be able to see the explanation, it should show us what RTH height it was set to and what it did on RTH...

Could have done with Active Track to track the bikes, would have been smoother, preferably with reverse flight enabled...

Yes the shot at the bikes was not good. I was not ready for them so i just went after to get anything.

Yes, bonefire. :p

Can you see this logfile?
http://www.dronelogbook.com/flig ... 4-BB9B-38450E98B3C1

Issue Posted at 2017-3-6 03:35
Yes the shot at the bikes was not good. I was not ready for them so i just went after to get anything.

Yes, bonefire. :p

I can see a page of data with map etc, but I don't see a way to download the file and get it into phantom help and I can't see anything that tells us what the aircraft though RTH was set for.

If you upload it to phantomhelp then people will have a look and may come up with something, we know how to use that website.

Nigel_ Posted at 2017-3-6 03:45
I can see a page of data with map etc, but I don't see a way to download the file and get it into phantom help and I can't see anything that tells us what the aircraft though RTH was set for.

If you upload it to phantomhelp then people will have a look and may come up with something, we know how to use that website.

I see. Trying to find the CSV file now in my app but i can not choose where to export it. Will try to figure this out as soon as i can. Im at work so might take a while if i dont find my dji logs on thr internet. Can they be accesed with the browser or only in app?

Issue Posted at 2017-3-6 03:53
I see. Trying to find the CSV file now in my app but i can not choose where to export it. Will try to figure this out as soon as i can. Im at work so might take a while if i dont find my dji logs on thr internet. Can they be accesed with the browser or only in app?

Is your measurements in feet that tree didn't look like 50 meters, just wondering ?

hallmark007 Posted at 2017-3-6 04:23
Is your measurements in feet that tree didn't look like 50 meters, just wondering ?

No, it is in meter. It is up on a hill and i started on the ice. If i set it to 80feet it would only accend to about 27meter. It ascended to ~50m before it started to head home.

I cant access the CSV or TXT log file now without the drone it seems. So i wont be able to upload to phantomhelp.com until i get home from work tonight. Sorry for the delay.

Issue Posted at 2017-3-6 04:28
No, it is in meter. It is up on a hill and i started on the ice. If i set it to 80feet it would only accend to about 27meter. It ascended to ~50m before it started to head home.

I cant access the CSV or TXT log file now without the drone it seems. So i wont be able to upload to phantomhelp.com until i get home from work tonight. Sorry for the delay.

The file you are looking for is a .txt file and you you don't need the drone to get it.

Are you aware of this from p18 of the manual?
It is a common explanation for what you describe:
If you move the left stick after the aircraft rises above 65 feet (20  meters) but below the  pre-set Failsafe RTH altitude, the aircraft will stop ascending and immediately return to the Home Point.

Labroides Posted at 2017-3-6 04:49
The file you are looking for is a .txt file and you you don't need the drone to get it.

Are you aware of this from p18 of the manual?

This is new to me. I can not remember if i moved the sticks after RTH was initiated. All i remember is that i tried to move to higher ground to get controll back.

But as it was out of reach for my controller, i should not make a difference with the controls?

Issue Posted at 2017-3-6 05:11
This is new to me. I can not remember if i moved the sticks after RTH was initiated. All i remember is that i tried to move to higher ground to get controll back.

But as it was out of reach for my controller, i should not make a difference with the controls?

You may have got a signal for a few seconds and happened to knock the stick at the same time while carrying the controller, the log file in phantom help will probably tell us if that happened.  It wont tell us much if you didn't have any signal though since it is recorded on the tablet, so hope for an explanation rather than expect one!

Nigel_ Posted at 2017-3-6 05:31
You may have got a signal for a few seconds and happened to knock the stick at the same time while carrying the controller, the log file in phantom help will probably tell us if that happened.  It wont tell us much if you didn't have any signal though since it is recorded on the tablet, so hope for an explanation rather than expect one!

Ok, will see if this if i case when i get into the log. Someone here will probably have to help me and read this infomation.

If it happens as you describe it. I should never touch anything when you lose connnection to the drone. If you do, you might crash it.. this is not good imo. Easy to make this mistake when you try to get back the control of the drone.

Imo, if it does not have connection to controller, it should only accend to RTH altitude and then return from that point, no mater what signals the controller sent before.

Mark The Droner Posted at 2017-3-6 03:09
I am not staff so I hope you don't mind if I comment.

It would be nice if you over-layed your altitude reading so we could see the measured height as it happens.

Could it be an inaccurate barometer reading in low temperature? It would be interesting to test how accurate it actually is at different temperatures.

piowoc73 Posted at 2017-3-6 05:49
Could it be an inaccurate barometer reading in low temperature? It would be interesting to test how accurate it actually is at different temperatures.

If it was incorrect it should also display 80m, right?

Sorry off topic but where is this ? its stunning ! never seen people on a frozen lake before on bikes

gregcrammond72 Posted at 2017-3-6 06:31
Sorry off topic but where is this ? its stunning ! never seen people on a frozen lake before on bikes

No problem. It is in sweden.

I have lived almost all my childhood years at this place and never seen bikes on the lake before. Wish i could get in contact with the bikes so i can record them better next time they want to have fun here.

Also took a panorama at this flight, you can see they had a good time. ;)https://500px.com/photo/20026720 ... weden-south-of-linköping-by-mickey-törnroth?ctx_page=1&from=user&user_id=20580089

Issue Posted at 2017-3-6 07:08
No problem. It is in sweden.

I have lived almost all my childhood years at this place and never seen bikes on the lake before. Wish i could get in contact with the bikes so i can record them better next time they want to have fun here.

Hi Issue, The video has great subject, I was in Sweden two weeks ago in upsala visiting my grandchildren, we went to frozen lake for some ice skating, really cool, although I didn't partake, was just taking video with my Osmo.

I think labroids may have put his finger on your problem, maybe go outside and try just to make sure..

Labroides Posted at 2017-3-6 04:49
The file you are looking for is a .txt file and you you don't need the drone to get it.

Are you aware of this from p18 of the manual?

Good info. I definitely overlooked that.

hallmark007 Posted at 2017-3-6 07:15
Hi Issue, The video has great subject, I was in Sweden two weeks ago in upsala visiting my grandchildren, we went to frozen lake for some ice skating, really cool, although I didn't partake, was just taking video with my Osmo.

I think labroids may have put his finger on your problem, maybe go outside and try just to make sure..

Yes but even if this is how it is intended to work, i think its bad. If you touch the left stick and that signal reaches the drone but you dont get control of it, it is high risk if crashing. Loads of obstacles at 20m.

I think it should, if there is no contact with RC, keep acsending no mater what command it got earlier. Dont you agree?

I will try this next time i get out and fly. See how it acts.

I checked the log on my ipad now, you can see the sticks and how they move while flying. No movement att all when it loses contact, but it takes a jump on the map so im not sure it would record it if there where any.

Hi… That tree that you almost hit was another 20 feet taller than where your drone was flying. 50 m is 164 feet that would put the tree at about 180 feet.  I don't know where you live, but I live in Maine (which is the most heavily forested to state in the country), and I would be surprised if we have any trees that are 180 feet tall… Just saying.

Zeldon50 Posted at 2017-3-6 08:15
Hi… That tree that you almost hit was another 20 feet taller than where your drone was flying. 50 m is 164 feet that would put the tree at about 180 feet.  I don't know where you live, but I live in Maine (which is the most heavily forested to state in the country), and I would be surprised if we have any trees that are 180 feet tall… Just saying.

I never said that the trees are 50m. They are on a hill and i started on the ice, on the lake.

But it is irrelevant. Drone is set to 80m RTH. When it breaks for trees it says it is at 50m.  Doesn't matter how tall the trees are or what the real altitude is, it is returning home lower than i asked it to do.

Okey dokey, have a nice day!

Zeldon50 Posted at 2017-3-6 08:15
Hi… That tree that you almost hit was another 20 feet taller than where your drone was flying. 50 m is 164 feet that would put the tree at about 180 feet.  I don't know where you live, but I live in Maine (which is the most heavily forested to state in the country), and I would be surprised if we have any trees that are 180 feet tall… Just saying.

UK's tallest tree is 217.10ft (66.4m), so even 80m wouldn't go over it standing on that hill - you may be underestimating how tall trees can grow!

Good to see it stop well short of the tree, I'd still like to see it back up a bit just to make sure it doesn't get caught on an overhang when climbing.

Issue Posted at 2017-3-6 07:41
Yes but even if this is how it is intended to work, i think its bad. If you touch the left stick and that signal reaches the drone but you dont get control of it, it is high risk if crashing. Loads of obstacles at 20m.

I think it should, if there is no contact with RC, keep acsending no mater what command it got earlier. Dont you agree?

Being able to cancel an unnecessary climb to high altitude when you can see it has a clear path home is very useful, it can also be essential if there is more wind high up than planned for.

The problem is when it reconnects, how fast should it start accepting commands again?  I think most people like it to start responding fairly fast.  I can only remember one thread where the climb was accidently cancelled resulting in a crash.  

Might be good if it required you to hold the left stick full down for three seconds to cancel the climb, not sure what the actual requirement is currently.

Nigel_ Posted at 2017-3-6 09:18
UK's tallest tree is 217.10ft (66.4m), so even 80m wouldn't go over it standing on that hill - you may be underestimating how tall trees can grow!

Good to see it stop well short of the tree, I'd still like to see it back up a bit just to make sure it doesn't get caught on an overhang when climbing.

Dont know if you are serious or trying to be funny.. :p I live in Sweden, not UK, and as i said before i been living there for 20 years, i know the place well and i knew 80m would avoid any trees between me and the drone.

Yea inded, would be nice if it backup the same way it came before trying to go over the obstacles.

Nigel_ Posted at 2017-3-6 09:18
UK's tallest tree is 217.10ft (66.4m), so even 80m wouldn't go over it standing on that hill - you may be underestimating how tall trees can grow!

Good to see it stop well short of the tree, I'd still like to see it back up a bit just to make sure it doesn't get caught on an overhang when climbing.

Actually, trees stop growing taller at a certain point in their lives. Their trunks will get larger but they do all top out at some point. Your trees are larger than ours here in Maine because of what species yours are.  Maine is known as the Pinetree state, as our pines are by far the tallest trees here, usually quite a bit taller than the deciduous ones.
zeldon50

Zeldon50 Posted at 2017-3-6 09:30
Actually, trees stop growing taller at a certain point in their lives. Their trunks will get larger but they do all top out at some point. Your trees are larger than ours here in Maine because of what species yours are.  Maine is known as the Pinetree state, as our pines are by far the tallest trees here, usually quite a bit taller than the deciduous ones.
zeldon50

I should have added to my last post that our trees here usually top out at about 120 feet. (36m).

Issue Posted at 2017-3-6 09:31
Dont know if you are serious or trying to be funny.. :p I live in Sweden, not UK, and as i said before i been living there for 20 years, i know the place well and i knew 80m would avoid any trees between me and the drone.

Yea inded, would be nice if it backup the same way it came before trying to go over the obstacles.

I was just responding to the suggestion that trees don't grow much taller than 180 feet tall.  I can see that your RTH height was sufficient.

I would probably have put it at 120m though since it would then have come back into signal range on the climb and you wouldn't have needed to come back, although it still spoils the video by turning towards home before starting the climb which seems unnecessary!

Nigel_ Posted at 2017-3-6 09:39
I was just responding to the suggestion that trees don't grow much taller than 180 feet tall.  I can see that your RTH height was sufficient.

I would probably have put it at 120m though since it would then have come back into signal range on the climb and you wouldn't have needed to come back, although it still spoils the video by turning towards home before starting the climb which seems unnecessary!

Ah, cool!

Yea but the point is it didn't go to set RTH altitude. Do you think it would have gone higher if i set it to 120m?

Zeldon50 Posted at 2017-3-6 09:30
Actually, trees stop growing taller at a certain point in their lives. Their trunks will get larger but they do all top out at some point. Your trees are larger than ours here in Maine because of what species yours are.  Maine is known as the Pinetree state, as our pines are by far the tallest trees here, usually quite a bit taller than the deciduous ones.
zeldon50

Actually, our tallest is currently a Douglas Fir, a species which I think comes your part of the world, it is also up in the Highlands of Scotland so will be a long way further north than yours, completely different climate though!

Nigel_ Posted at 2017-3-6 09:29
Being able to cancel an unnecessary climb to high altitude when you can see it has a clear path home is very useful, it can also be essential if there is more wind high up than planned for.

The problem is when it reconnects, how fast should it start accepting commands again?  I think most people like it to start responding fairly fast.  I can only remember one thread where the climb was accidently cancelled resulting in a crash.  

I dont think it is a problem if it start to respond right away. But as the connection never was stable(lost again and no videostream) it should ignore the" altitude climb cancel" from left stick and start climb again. That is how i would like it to act.

I really hope we can see in the log if i did cancel the climb with stick.

Ok, im home from work and here is the log uploaded to phantomhelp.com!

http://www.phantomhelp.com/LogViewer/V70IR084QJU8QQTUBFHM/#

Let me know if you want anything else. I cant read out any stick movement at this site.

Well it clearly says that it is set to RTH at "80m" altitude, and when the link is restored it is just setting off back at 46.6m altitude having been at 37.1m when the link was lost.  At the time the link is restored you are not touching the controls.

I guess it is possible that you did touch the controls earlier and the link only sent data one way, but that would not be good, it should make a proper connection before accepting data.

One thing I find odd is that when the link is restored, the first message is "Camera Settings Adjusted to ActiveTrack", which doesn't make sense since you are not using ActiveTrack and I've not noticed that happen in other logs.  You had been using ActiveTrack earlier so I wonder if something got messed up with the RTH because of the earlier use of ActiveTrack.

If nobody else can explain it, it might be worth extracting the log from the aircraft and ask DJI support to analyse it, pointing out the odd ActiveTrack message as well as the incorrect RTH height.  Even if you don't send it now, it may be worth saving it for later.

I'm also a bit puzzled by the velocity figures, it doesn't seem to ever fly straight forwards, always at an angle!

Nigel_ Posted at 2017-3-6 15:37
Well it clearly says that it is set to RTH at "80m" altitude, and when the link is restored it is just setting off back at 46.6m altitude having been at 37.1m when the link was lost.  At the time the link is restored you are not touching the controls.

I guess it is possible that you did touch the controls earlier and the link only sent data one way, but that would not be good, it should make a proper connection before accepting data.

Thanks for the replay and help analyzing the log.

I did use active track at the bonfire right before i head out to shoot at the bikes. I think the shooting mode(like tripod, follow me, active track) was still set to active track for the rest of the flight. Just not started. I'm not sure tho.

How can you see there was no stick movement when connection is lost? Did you download a file to see this?

Ok, so i connect the aircraft to PC and use DJI assistant software to get the "big" logfile?
-
Edit, about the "velocity figures". If you mean it doesnt "look" at the direction it is flying. This is a problem i have often. I always thought it was a bug or compass calibration needed. Sometimes it is more, sometimes its less.

Yes, if DJI are going to work out what happened then I think they will need the big log from DJI Assistant.  But sync your flight records and request they look at them first, then send the big log if they ask for it.

I downloaded the CSV file (link just below map) and looked at it in Microsoft Excel, that has a column for each stick movement.

It says it is in P-GPS mode most of the time, but I'm not sure if that means ActiveTrack was completely off.  I did notice that you get one of those "Camera Settings Adjusted to ActiveTrack" messages a little before it goes into ActiveTrack mode, so maybe it only shows ActiveTrack when it is actually locked on to something.

The not flying straight issue is odd, it knows it is doing it, and I can't see why compass calibration would make a difference.  Must be due to some other calibration.   Does the camera point in the direction of travel, or in the direction the aircraft is pointing?   I've not noticed it in logs from other aircraft.

Nigel_ Posted at 2017-3-6 16:23
Yes, if DJI are going to work out what happened then I think they will need the big log from DJI Assistant.  But sync your flight records and request they look at them first, then send the big log if they ask for it.

I downloaded the CSV file (link just below map) and looked at it in Microsoft Excel, that has a column for each stick movement.

Ah ok, will try the CSV file tomorrow.

Yes, i think it shows p-gps when it is not locked. Only the icon on the left side of screen is showing. I can see that it goes to p-gps right after i cancel lock on bonfire.

I can see the camera is not going straight forward, that is how i always notice this issue. It is easy to spot as the terrain is not moving at the same speed on the left and right edge of my ipad screen.

Will try to do a IMU calibration and compass before next flight and see if that helps. If not i will try contact support.

You can clearly see that you are no where close to 80m. I have only had an RTH 1 time and it went as it was supposed to. I have had altitude issues a couple of times. One of those left me parked in a tree. A tree that is actually what I set my flight altitdue for.

I have had a quick look at the CSV file.

There is a loss of signal for 19.2 seconds when it initiates a "GO HOME" and it then starts to climb.

At 25m 17.5s there is an input from the throttle (left stick) to increase altitude. According to the information above this may set the new RTH altitude. The OA then saved a crash.

That is what I can see on a very quick look